Representative DURHAM. Well, we would have to depend upon them entirely as volunteers, even after we had trained them with Government funds.

Dr. DUNHAM. Right.

Representative DURHAM. What I am thinking about is some relationship or some way that we could assimilate this and have it as a known fact that we have a lot of people already trained in this field. But they are scattered all over the country, so that we have nothing to get them together quickly.

Dr. DUNHAM. I think the work on this radiological assistance plan, as we call it—it is an interagency committee, and the Commission is having a meeting with its own staff, I think, Thursday, going over a final version of this. This I think will develop just the type of information, who has the capability, who is trained, and what organizations they relate to, if any.

Representative DURHAM. I think it is well for you to do the training, because the facilities will naturally present the hazards and some of the problems. But after all, I think it is probably the responsibility of the Office of Defense Mobilization to put this thing together and have it available in case something does happen. We have not got but one policy today, and that is one of massive retaliation. We might just as well face it. That is what it would be. Of course, it is all right for the Defense Department to have this available, but I think the civilians have a little interest in this also.

Dr. DUNHAM. A very vital interest in it.

Representative DURHAM. Very vital. I hope you will pursue that matter, since you can get the money when some of the agencies cannot get the money. And I think it will continue to be given to you, because it is a good program and a worthwhile program.

Representative HOLIFIELD. I just want to affirm what Congressman Durham has just said.

I think a great responsibility rests upon the agency, because they have a background of experience in this field and they have also been accorded a generous set of appropriations to conduct these studies. And I believe along the line of the discharge of responsibility of the agency, each one of us that has knowledge in this field has a personal responsibility that is charged to the people who do not have access to a great deal of this information. And it is my continued hope that these hearings and hearings will be held in the future—will bring out these facts, so that people who are entitled to have them-and by that I mean the whole of the American people can have access to anything that we have in a factual way to make up their minds as to the solutions for this great problem of radioactivity.

I am hoping that the hearings on the effects of a nuclear war will receive your attention, and you will be able to bring out a great deal of information which will relate to the problems of defense which we are so interested in.

How many men have you trained in the overall program in the last few years.

Dr. DUNHAM. It depends upon the degree of training one is talking about. If you are talking about an individual whom we would call a radiological health scientist, we have probably trained, by special courses and that sort of thing, a matter of several hundred.

Meanwhile, others have developed in actual plant operations, on-thejob type of training. And as I indicated, we have about a thousand, all together, very highly trained people in our whole operations, as well as professionally trained people to assist.

Mr. RAMEY. In earlier hearings, Dr. Shields Warren mentioned studies that you had undertaken on employees as to their later work and health experience, employees who had been possibly exposed to radiation at your facilities. The committe staff followed up on that and it turned out that apparently you had not made a very detailed statistical analysis of this type of information, but that you had one possible pilot study underway at Argonne.

With your atomic energy installations, is this not one of the best sources of statistical data? You have been in operation now for 18 years. Is this not something that would prove fruitful? Dr. DUNHAM. I think eventually it will, Mr. Ramey.

There are two problems, really. One: It is a very small percentage of the employees that get appreciable exposures to radiation.

I was interested in a paper that came out in Science just last weekend by a Canadian who figured out that you would have to have a population of 6 million in order to tell the difference in leukemia incidence among those who had a difference of as much as 5 roentgens total exposure.

The other is a matter of time. And we will certainly make such studies. And as the information we pass to you indicated, there just has not been time enough, with the low levels we are talking about, to expect anything very exciting.

You will recall that the actual incidence noted was lower than that in the population as a whole. We do not think this is a valid inference, because it is just not a complete enough study, and we do not have a big enough population with enough exposure over enough

years.

Mr. RAMEY. Would not this be something that you could put a statistician on—someone trained in this sort of field?

Dr. DUNHAM. Oh, yes.

Representative DURHAM. Thank you very much, Doctor.

We will have to adjourn the meeting, and we will resume again at

2 o'clock,

We are sorry we could not get through with all the witnesses this morning, but there is a bill on the floor of the House that some of us are interested in.

Thank you very much.

The committee is adjourned until 2 o'clock.

(The balance of Dr. Dunham's statement referred to on p. 29 follows:)

STANDARDS OF RADIATION PROTECTION

In small amounts, radiation is a phenomenon of nature to which every living creature is subject. Cosmic rays from outer space; gamma radiation from radium and its radioactive decay products in the earth's crust; and alpha, beta, and gamma radiation from radium and the radioactive isotopes of hydrogen, carbon, and potassium which occur naturally in the human body, combine to give body tissues an average radiation dose equivalent to about one-tenth of a roentgen of X-rays per year. To what extent such small doses of radiation may be harmful, we do not know. Certainly the human race has developed and prospered in an environment of which this has been one of the more stable characteristics.

In much larger amounts, radiation results in observable injury to all living things. For example, an accidental exposure to three or four hundreds of roentgens of X-rays will result in radiation sickness and could, under unfavorable conditions, be fatal. At best, 2 or 3 months would be required for more or less complete recovery from apparent effects. Such recovery does not preclude the possibility of delayed effects such as leukemia or reduction in life span, nor of genetic mutation.

in routine activities involving exposure to radiation, we are concerned with doses of radiation sufficiently small that, up to the present time, the resultant effects on health cannot be observed. Nevertheless, it is considered prudent to assume that even the smallest exposures to radiation involve biological hazards which are correspondingly small. However, no one so far as we are aware proposes that there should be no exposure to manmade sources of radiation. Rather, the problem of control of radiation hazards is to limit possible risks to acceptable levels. In principle, this appears to be feasible, since we are confident that it is possible to make the resultant hazard as small as one may wish by sufficiently limiting the exposure. While we cannot estimate with confidence the actual hazards from exposure to low levels of radiation, it is believed that we can estimate upper limits which the actual hazards are not likely to exceed. The lower limit may, of course, be zero.

Exposure to manmade sources of radiation cannot be justified unless the reasons for accepting the exposure outweigh the hazards involved. This means that in any case the benefits to be anticipated from any activity involving exposure to radiation must be greater than the risk. However, it implies more than this. If there is an alternative method by which the same objective can be accomplished with less exposure to radiation, such alternative method should be used, provided that the reduction in exposure is sufficient to justify additional cost, effort, or other disadvantages of the alternate method.

To provide a reasonable balance of radiation hazards against reasons for accepting exposure to radiation involves several difficulties. Such a balance does not depend alone upon our knowledge of the relationships between radiation exposure and their biological effects. It is necessary also, but even more difficult to evaluate benefits to be anticipated from the various activities which may result in exposure to radiation. Furthermore, there are no common units of measure which can be used in comparing risk to benefit. It follows that establishing realistic standards of radiation protection involves not one but three areas in which there may be expected to be wide differences in individual judgment. These differences can be reduced in time by more precise quantitative knowledge in two of the areas—those involving the biologic effects of radiation and, to a lesser extent, the anticipated benefits from activities involving exposure to radiation. There appears no reason to believe, however, that regardless how well informed we become there will ever be unanimity with respect to the maximum degree of biologic risk which can be justified by a particular economic, social, or political goal. In a complex social structure, decisions involving such questions are valid only to the extent that they represent a consensus of well-informed persons.

One of the complications in evaluating benefits from activities involving risk from radiation is that the benefits do not necessarily accrue to the individuals who undergo the exposure. This situation is not peculiar to the problem of radiation protection. It is paralleled by other demands upon the individual throughout our complex social organization. It does, however, constitute a compelling reason to keep the risk very small. This pressure is reflected in a criterion of radiation protection, frequently quoted but extremely difficult to interpret, that the risks from exposure to radiation should be small compared to other risks which persons customarily accept.

In general, standards of radiation protection are meaningful only in relation to the conditions for which they are formulated. For example, occupational limits are designed to limit the risk than any individual employee should be expected to accept in connection with his routine duties. They may be much lower than exposures which would be appropriate in an emergency in which there were strong reasons for accepting such exposures. On the other hand, the mere existence of an accepted occupational limit does not justify individual occupational exposures to radiation which it is practical to avoid by such methods as technical improvements of process, training of the employee, and general precautionary procedures.

Even in this brief discussion of the problems involved in arriving at appropriate limits of radiation exposure, it is obvious that not only is the problem very complex but many of the considerations involved are of such a nature that one may expect wide differences in their evaluation. Occupational standards of radiation protection used in the United States and generally in other countries are consistent with basic standards recommended by the National Committee on Radiation Protection and Measurements and the International Commission on Radiological Protection with which it is affiliated. Hereinafter, these groups are respectively referred to as the NCRP and the ICRP.

The NCRP, sponsored by the U.S. National Bureau of Standards, was founded as the International X-ray and Radium Protection Committee in 1929. At the present time it consists of a main committee which has the responsibility for the commendations made by the NCRP, and a dozen subcommittees working on various aspects of radiation protection.

The main committee is composed of representatives of various agencies and organizations considered to have especial interest and competence in problems of radiation protection, plus two members-at-large. Representatives of the various agencies or organizations are specifically designated by the groups which they represent, while members-at-large are elected by the main committee. Members of subcommittees are selected by the NCRP on the basis of individual qualifications, without regard to their organizational affiliations. Currently representation on the main committee includes U.S. Public Health Service, American Industrial Hygiene Association, International Association of Government Labor Officials, Radiological Society of North America, American College of Radiology, U.S. Atomic Energy Commission, American Radium Society, Health Physics Society, American Medical Association, U.S. Air Force, Atomic Industrial Forum, U.S. Army, American Dental Association, American Roentgen Ray Society, National Electrical Manufacturing Association, National Bureau of Standards, and the U.S. Navy.

A survey of the experience and background of the members of the NCRP and of its subcommittees discloses a very impressive cross section of the Nation's knowledge and experience in the field of radiation protection. Further, the committee works closely with leaders in this field in foreign countries both through the International Commission on Radiological Protection and by personal contact. These factors provide an unmatched opportunity for a consensus of informed opinion on questions of radiation protection, with the result that these organizations are universally acknowledged as the most authoritative organizations dealing with problems of radiation protection. Their recommendations on basic standards of radiation protection for occupational workers are accepted internationally both by national groups and by such international groups as the World Health Organization, the International Labor Office, and the International Standards Organization.

There appears to be no question that the recommendations of the NCRP and the ICRP represent the most authoritative guides now available for the protection of workers in industry. There is also no question that these recommendations are and should be subject to change not only as better definitions of the biological risks from exposure to radiation is achieved, but also to reflect developments in such factors as technical ability to control radiation risks, potential contributions of nuclear energy to the common welfare, and general standards of occupational risk.

The basic recommendations of the NCRP and the ICRP are those dealing with actual exposure of the whole body or of major organs of the body to radiation. Related to these are derived standards which deal with concentrations of specific radioactive materials in air and water. These derived standards are estimated to be sufficiently low in that they would not during a lifetime result in exposures of the body or major organs of the body to levels of radiation in excess of those recommended in the basic standards. These secondary standards are subject not only to the uncertainties which may be involved in the basic standards for exposure but in addition to any uncertainties as to the retention and distribution of the individual radioactive materials in the body, and as to the relative importance of nonuniformities in such distribution.

To provide assistance in meeting these basic and secondary standards, and to make it more probable that these standards will be met, the NCRP also makes many recommendations concerning such subjects as measurements of exposure to radiation and of levels of radiation or of radioactivity, good radiation safety practices, and administrative controls. The details of such

recommendations should not be considered mandatory; in fact, under some circumstances there may be methods of accomplishing the same results which are as good or even better than those specifically recommended by the NCRP. There are other areas in which it is as yet impossible to formulate a single set of detailed recommendations that will be applicable under the diversity of conditions to be found in practice. The important consideration is that in any operation the overall operating procedures shall be controlled to conform as closely as possible with the basic standards of radiation protection.

It is quite likely that firmer scientific bases for fundamental standards of radiation protection will come from laboratory research which contributes to a better understanding of the mechanisms of induction of such diseases as leukemia and cancer rather than from applied research planned to obtain quantitative answers to specific questions. The problems of determining, for example, whether or not there is a threshold for the production of leukemia and of cancer by radiation and of how the incidence of either of these diseases depends upon radiation doses at very low rates of exposure is similar to—and may be identical with—that of discovering how these diseases are produced. Medical science has made encouraging progress over the past several decades in gaining an understanding of the fundamental mechanisms involved, but the many competent scientists engaged in this field of research have so far been unable to give us answers adequate to our needs.

On the other hand, the development of secondary standards depends very largely on obtaining specific quantitative data on the biochemical and physical characteristics of individual radioisotopes in relation to their retention and distribution in the various organs or tissues of the body. Thus, research designed to reduce the uncertainties involved in our standards of radiation protection should strike a balance between the effort expended to obtain answers to specific questions and that for increasing our fundamental knowledge of mechanisms involved in producing the biological effects of radiation. Before leaving this phase of the discussion it should be observed that few if any of the industrial toxins have been subject to such a relentless scrutiny for possible small effects of low concentration on average life span, for the ability to produce small statistical increases in cancer or leukemia, etc., as has ionizing radiation.

LIMITS FOR POPULATION GROUPS

The determination of appropriate limits for the control of exposures of population groups to radiation is more difficult than for the control of occupational exposures for several reasons. Up to the present time, this problem has been met by using for environmental limits a small fraction of occupational limits. The fraction one-tenth, used for this purpose by the Atomic Energy Commission since 1951, was recommended by the ICRP in 1954 and by the NCRP in 1955. In their most recent reports, both the NCRP and the ICRP recommend that exposures to population groups in the neighborhood of atomic energy installations be limited to one-tenth of occupational values.

In addition, the ICRP recommends fractions applicable to the total population. For exposures of genetic significance, the recommended fraction is onehundredth and for other exposures one-thirtieth. Except for the recommendation that the average genetic exposure to the total population from all sources should not exceed a total of 14 rem per generation of 30 years, the NCRP has made no recommendations applicable to the total population.

(Whereupon, the committee recessed at 12:30 p.m., to reconvene at 2 p.m. the same day.)

AFTERNOON SESSION

Chairman ANDERSON. The committee will be in order.

I understand that the first witness this afternoon is Dr. Joseph Lieberman.

Mr. GRAHAM. Yes, sir; we have him here. With your permission we will start him right away.

Chairman ANDERSON. You may proceed.